If no preferences file is available, or values are missing, use default values for the UI

Load and set joystick value in GUI Prefs dialog

Mark new source files as translateable, mark new strings as translateable, modify Makefile for better RPM support (SF patch 2035285 - thanks Ugo Viti). Italian translation is now at 100%.

Set default button on the dialogs to be the Close button

Added support to launch the GMAMEUI Help manual. This will use gtk_show_uri (if GTK > 2.13 is installed), or revert to libgnome's gnome_url_show. Users who do not wish to compile in libgnome (e.g. XFCE or KDE users) will need to explicitly disable it by compiling with --disable-libgnome, but will not be able to access the manual from within GTK